Mankind is dependent upon field crops for food, fiber, animal feed and the like. The ever-increasing world population dictates the necessity to produce more from each hectare and, at the same time, to preserve and protect the environment and natural resources that make such production possible. Successful crop production and environmental concerns lead to an ongoing need for new and effective methods to control pestiferous plants which provide early season weed competition and late season weed flushes causing significant loss in crop quality and yield.
Herbicidal 2,6-disubstituted pyridines and 2,4-disubstituted pyrimidines are described in EP 723,960. Said compounds contain a heteroaryloxy group in the 2 or 6 position wherein the heteroaryl moiety contains at least one nitrogen atom. Although many of these disclosed pyridine and pyrimidine compounds demonstrate efficacious control of a variety of weeds, said compounds are not completely satisfactory with regard to crop selectivity and consequently may have limited application in agricultural practice.
It has now been found that the 2-(thienyloxy)-pyridine and 6-(thienyloxy)pyrimidine compounds of the present invention are particularly useful as crop-selective herbicidal agents.